EP-A-0223905 discloses a padlock-type seal which comprises a plastic housing having a pair of apertures for receiving a shackle formed of a U-shaped piece of wire. The shackle can be passed over the member to be locked and pushed into the housing, to irreversibly lock therein. The seal is released by cutting of the wire. This particular seal cannot be reused.
U.S. Pat. No. 5,230,541 discloses a seal which is in the form of a fastener for cabinets. The fastener is closed by means of a flexible, elongated band which engages on first and second latches within the fastener body. The band can be released for reuse.
WO-A-97/48603 discloses a seal having a J-shaped hasp which may be locked in the seal housing by means of a pressure sensitive catch. The seal can be opened by one leg of the hasp being cut. A product based on the design of WO-A-97/48603 is manufactured and sold by ITW Envopak under the name “Padseal” (registered trade mark). This product has a J-shaped hasp with parallel arms which are inserted into slots within the seal housing. The arms are locked within the housing by means of a sprung catch. The hasp is removed by one leg being cut, the lower part of that leg then being pulled out of the bottom of the housing, which allows the remained of the hasp to be removed from the top.